Rho-omega mixing and the pion form factor in the timelike region

Abstract

We determine the magnitude, phase, and $s$ dependence of $\ensuremath{\rho}$-$\ensuremath{\omega}$ ``mixing'' in the pion form factor in the timelike region through fits to ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ data. The associated systematic errors in these quantities, arising from the functional form used to fit the $\ensuremath{\rho}$ resonance, are small. The systematic errors in the $\ensuremath{\rho}$ mass and width, however, are larger than previously estimated.